--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_trans.h"
+#include "xfs_btree.h"
+#include "xfs_trace.h"
+#include "xfs_btree_staging.h"
+
+/*
+ * Staging Cursors and Fake Roots for Btrees
+ * =========================================
+ *
+ * A staging btree cursor is a special type of btree cursor that callers must
+ * use to construct a new btree index using the btree bulk loader code. The
+ * bulk loading code uses the staging btree cursor to abstract the details of
+ * initializing new btree blocks and filling them with records or key/ptr
+ * pairs. Regular btree operations (e.g. queries and modifications) are not
+ * supported with staging cursors, and callers must not invoke them.
+ *
+ * Fake root structures contain all the information about a btree that is under
+ * construction by the bulk loading code. Staging btree cursors point to fake
+ * root structures instead of the usual AG header or inode structure.
+ *
+ * Callers are expected to initialize a fake root structure and pass it into
+ * the _stage_cursor function for a specific btree type. When bulk loading is
+ * complete, callers should call the _commit_staged_btree function for that
+ * specific btree type to commit the new btree into the filesystem.
+ */
+
+/*
+ * Don't allow staging cursors to be duplicated because they're supposed to be
+ * kept private to a single thread.
+ */
+STATIC struct xfs_btree_cur *
+xfs_btree_fakeroot_dup_cursor(
+ struct xfs_btree_cur *cur)
+{
+ ASSERT(0);
+ return NULL;
+}
+
+/*
+ * Don't allow block allocation for a staging cursor, because staging cursors
+ * do not support regular btree modifications.
+ *
+ * Bulk loading uses a separate callback to obtain new blocks from a
+ * preallocated list, which prevents ENOSPC failures during loading.
+ */
+STATIC int
+xfs_btree_fakeroot_alloc_block(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *start_bno,
+ union xfs_btree_ptr *new_bno,
+ int *stat)
+{
+ ASSERT(0);
+ return -EFSCORRUPTED;
+}
+
+/*
+ * Don't allow block freeing for a staging cursor, because staging cursors
+ * do not support regular btree modifications.
+ */
+STATIC int
+xfs_btree_fakeroot_free_block(
+ struct xfs_btree_cur *cur,
+ struct xfs_buf *bp)
+{
+ ASSERT(0);
+ return -EFSCORRUPTED;
+}
+
+/* Initialize a pointer to the root block from the fakeroot. */
+STATIC void
+xfs_btree_fakeroot_init_ptr_from_cur(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *ptr)
+{
+ struct xbtree_afakeroot *afake;
+
+ ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
+
+ afake = cur->bc_ag.afake;
+ ptr->s = cpu_to_be32(afake->af_root);
+}
+
+/*
+ * Bulk Loading for AG Btrees
+ * ==========================
+ *
+ * For a btree rooted in an AG header, pass a xbtree_afakeroot structure to the
+ * staging cursor. Callers should initialize this to zero.
+ *
+ * The _stage_cursor() function for a specific btree type should call
+ * xfs_btree_stage_afakeroot to set up the in-memory cursor as a staging
+ * cursor. The corresponding _commit_staged_btree() function should log the
+ * new root and call xfs_btree_commit_afakeroot() to transform the staging
+ * cursor into a regular btree cursor.
+ */
+
+/* Update the btree root information for a per-AG fake root. */
+STATIC void
+xfs_btree_afakeroot_set_root(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *ptr,
+ int inc)
+{
+ struct xbtree_afakeroot *afake = cur->bc_ag.afake;
+
+ ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
+ afake->af_root = be32_to_cpu(ptr->s);
+ afake->af_levels += inc;
+}
+
+/*
+ * Initialize a AG-rooted btree cursor with the given AG btree fake root.
+ * The btree cursor's bc_ops will be overridden as needed to make the staging
+ * functionality work.
+ */
+void
+xfs_btree_stage_afakeroot(
+ struct xfs_btree_cur *cur,
+ struct xbtree_afakeroot *afake)
+{
+ struct xfs_btree_ops *nops;
+
+ ASSERT(!(cur->bc_flags & XFS_BTREE_STAGING));
+ ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE));
+ ASSERT(cur->bc_tp == NULL);
+
+ nops = kmem_alloc(sizeof(struct xfs_btree_ops), KM_NOFS);
+ memcpy(nops, cur->bc_ops, sizeof(struct xfs_btree_ops));
+ nops->alloc_block = xfs_btree_fakeroot_alloc_block;
+ nops->free_block = xfs_btree_fakeroot_free_block;
+ nops->init_ptr_from_cur = xfs_btree_fakeroot_init_ptr_from_cur;
+ nops->set_root = xfs_btree_afakeroot_set_root;
+ nops->dup_cursor = xfs_btree_fakeroot_dup_cursor;
+
+ cur->bc_ag.afake = afake;
+ cur->bc_nlevels = afake->af_levels;
+ cur->bc_ops = nops;
+ cur->bc_flags |= XFS_BTREE_STAGING;
+}
+
+/*
+ * Transform an AG-rooted staging btree cursor back into a regular cursor by
+ * substituting a real btree root for the fake one and restoring normal btree
+ * cursor ops. The caller must log the btree root change prior to calling
+ * this.
+ */
+void
+xfs_btree_commit_afakeroot(
+ struct xfs_btree_cur *cur,
+ struct xfs_trans *tp,
+ struct xfs_buf *agbp,
+ const struct xfs_btree_ops *ops)
+{
+ ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
+ ASSERT(cur->bc_tp == NULL);
+
+ trace_xfs_btree_commit_afakeroot(cur);
+
+ kmem_free((void *)cur->bc_ops);
+ cur->bc_ag.agbp = agbp;
+ cur->bc_ops = ops;
+ cur->bc_flags &= ~XFS_BTREE_STAGING;
+ cur->bc_tp = tp;
+}
__entry->calc_rootino)
)
+TRACE_EVENT(xfs_btree_commit_afakeroot,
+ TP_PROTO(struct xfs_btree_cur *cur),
+ TP_ARGS(cur),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_btnum_t, btnum)
+ __field(xfs_agnumber_t, agno)
+ __field(xfs_agblock_t, agbno)
+ __field(unsigned int, levels)
+ __field(unsigned int, blocks)
+ ),
+ TP_fast_assign(
+ __entry->dev = cur->bc_mp->m_super->s_dev;
+ __entry->btnum = cur->bc_btnum;
+ __entry->agno = cur->bc_ag.agno;
+ __entry->agbno = cur->bc_ag.afake->af_root;
+ __entry->levels = cur->bc_ag.afake->af_levels;
+ __entry->blocks = cur->bc_ag.afake->af_blocks;
+ ),
+ TP_printk("dev %d:%d btree %s ag %u levels %u blocks %u root %u",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __print_symbolic(__entry->btnum, XFS_BTNUM_STRINGS),
+ __entry->agno,
+ __entry->levels,
+ __entry->blocks,
+ __entry->agbno)
+)
+
#endif /* _TRACE_XFS_H */
#undef TRACE_INCLUDE_PATH
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